Fire escape



Dec, 1, 1937. B. VALE 2,101 6 9 FIRE ESCAPE Filed Aug. 26, 1936 3Sheets-Sheet 1 FIG. 2. I W

FIG. I

-|NVENTORI Dec. 7, 1937. B. vAL

FIRE ESCAPE Filed Aug. 26, 1936 3 Sheets-Sheet 2 FIG; 3.

IN VENTO R:

B. VALE FIRE ESCAPE Dec. 7, 1937.

Filed Aug. 26, 1936 3 Sheets-Sheet 3 FIG. 5.

Patented Dec. 7, 1937 V s f- UNITED STATES PAT-E This invention relatesto improvements in fire escapes and more particularly to automaticextension stairs therefor.

- Among the objects of the invention is to provide' an inclined stairextension applicable to the conventional fire escapes, which maybenormally suspended in a vertical position and automatically lowered'into inclined relation to the ground and the first balcony.

'Another object is to provide a fire escape extension stair whichconforms to the regulations 'governingsuch structures, that is strong,simple, free fromsmall and intricate parts subject toclimaticdeterioration and mechanical failure at 1 critical moments. a lh Another object is to 'd' celerate the descent of the stair intooperative position; Anotherobject is to avoid the danger of injury tosidewalks and pedestrians in lowering the stairs.

.Afurther object is to divert the stair during its vertical descent tothe inclined operative position just prior to the end of the descent.

Other objects and advantages will appear as 25. the descriptionprogresses.

- In this specification andthe accompanying drawings the invention isdisclosed in its application to a conventional condition. However, it isto be understood that it is not limited to this form because it may beembodied in other forms within the purview of the claims following thedescription; W

- i In the three sheets of drawings:

[is a side elevation of a fire escape having an extension stairconstructed and combined therewith in accordance with this invention.The extension is shown in the operative position. Fig. 2 is a frontelevation of the same, with the extension raised into inoperativeposition.

Thehand rail has been omitted in this view.

Fig. 3 is an enlarged detail in side elevation of the upper portion ofthe installation, showing the hoisting and suspension assembly with thehead of the extension stair in the inoperative position. i

Fig. 4'is an end elevation of the same showing the windlass locking pawlin the operativeposi tion. The head of the stair has been omitted inthis figure;

Fig. 5 read in conjunction with Fig. 4, shows the head of the stair inoperative relation to the lower balcony bracket.

In detail the structure illustrated in the drawings referring first toFig. 2, comprises the con-- .55 ventional balcony platforms l and 2rigidly fixed to the building wall 3 and having the enclosing railingssuch as 4 and 5, respectively. The balconies are usually constructed ofconventional steel shapes, with various architectural modifications indesign. a

The interspaced standards 6 and i are bolted at 8 and 9 to the upperplatform I and fastened to the top rail 4 by clamps such as l0, seeFigs. 1 and 4. The U shape Windlass yoke, see Fig. 3,

has the cross plate, ll fixed to the standards 6 10' and l by the upperends of the guide rods I2 and I3 between the nuts l4, l5 andlB, I1respec' tively. The front extensions of the clamp l0 are also interposedbetweenthe standards 6, l and the plate II, the whole assembly being,drawn 15 tight between the respective nuts l4l'|, see

Fig.3.

The upward side extension. l8 of the yoke has the bearing IQ for thetrunnion 29 on the windlass head 2i. The opposite extension 22 has the20 square thimble 23 forced snugly through a square hole therein toprovide a non-turning anchorage for the shaft 24 fixed therein by thetransverse taper pin 25.

The opposite head 26 of the windlass has the 25 stuifing box 21encircling the shaft 24 upon which it revolvesfreely. The Windlasscomprises the cylinder 28, fixed within the opposed heads 2! and 26 to'forma pressure-tight cylinder freely 'revolvable on the trunnion 20and'the shaft 24 30 between the yoke sides l8and 22 g The head 26 hasthe spur gear 29 thereon enmeshed with the pinion 30 fixed by the pin 3ion the crank shaft 32, extending through the yoke sides I8, 22 andterminating in the hand 5 crank 33. The pinion has the flange 34 bearingagainst the side of the gear 29 under the pressure exerted by the spring'35 when the gear and the pinion areenmeshed for rotating the Windlass.The pinion3ii can be disengaged from 42 the gear 29 by sliding the shaft32 longitudinally and inserting a. pin through the hole 36 when it isbeyond the yoke side 22. This is a precautionary measure to prevent thecrank 33 revolving during the unwinding of the Windlass and strik-' 45ing an occupant of the upper balcony.

.To prevent the unwinding of the Windlass the pawl 31 is provided, seeFig. 4. This pawl has .the pin 38' pivoted in the bearings 39, 40 formedin theplate 4|, held beneath the nut 14. This 50 pawl has the teeth 42,43 thereon adapted to mesh with the teeth on the gear 29. The pull' wire44 depending from the end of the pawl, extends through the grating ofthe upper platform and V has. the handle 45 attached thereto within easy7 N OFFICE reach of an adult person on the lower platform 2. It is alsoadvisable that it extend below the lower platform 2 and terminate in thering 46 within reach of a firemans hook.

The vertical guide rods l2, l3 extend downward and through the lowerbracket 47, bolted at 48 to the lower platform I, see Fig. 5. Thisbracket has the forward extension 49 through which the rods l2, I3 passand to which they are firmly fixed by the nuts 50, El and 52, 53respectively. The bracket is slit adjacent each end and the centerportion 54 curved downward to form a fulcrum for the extension stair.

Referring to Fig. 2 this stair comprises the side stiles 55, 56 joinedby the threads 51 at proper intervals. The length of this extensionstair is equal to the distance from the first platform I to the groundat the usual stair inclination. The upper ends of the stiles are bentoutward to form the angular heads 58, 59 respectively. The respectiverods l2 and l3 pass through enlarged openings in these heads to guidethe descent of the stair.

The hoisting cable has its center portion or bight 68 passed through thestaple 6| butt welded to the periphery of the Windlass cylinder 28, seeFig. 3. The cable length equal to the descent of the stair is woundaround the Windlass in opposite directions until its opposite extensions62, 63 descend between the standards 6, l and are fixed in theirrespective heads 58, 59 as at 64, 65. The whole weight of the extensionstair is thus suspended by the cable ends 62, 63 and the Windlass whichis locked by the pawl'3'l.

The pawl is so arrangedthat the Windlass gear 29 must be advanced onetooth by the swing of the pawl on its center 38, so that the weight ofthe stair suspended thereby must be lifted before the teeth 42, 43disengage and release the windlass.

When the Windlass is thus released the weight of the suspended stairrotates the Windlass to unwind the cable. The stair is guided in itsdescent by the vertical guide rods l2, l3; the equalized tension of thecable ends-62, 63; and by the extensions 66, 61 of. the plate 49 lateralto the fulcrum '54. a

This fulcrum being lateral to the longitudinal center of the width ofthe side stiles 55, 56, which are centered on the guide rods, causes acramping action when the stair approaches the end of its descent, seeFig. 5. This causes the lower end of the stair to swing outward to thedesired inclination before coming to rest upon the ground. This featureof the operation is meritorious because the path of descent of the stairis often restricted by awnings, signs and architectural projections fromthe wall 3. It has the further advantage that the end of the staircannot break through the side walk nor guillotine a pedestrian, sincethe out swing occurs relatively close to the ground. The progressiveangle of the outswing increases the friction against the fulcrum 54tending to retard the descent in addition to the decelerating effect ofa change of direction.

Since such extension stairs weigh about six hundred pounds, more or lessaccording to length, it is necessary to decelerate their descent. In thepresent instance this is accomplished by liquid displacement, see Fig.3.

The threaded portion 68 of the shaft 24 engages the running nut 69forming the hub of a piston of any desired construction, such as the cupleather 1c clamped between the flange H of the hub and the disk E2. Thethreaded portion 68 .of

the shaft 2t is held stationary as previously described and has its end13 journaled in the step bearing 14 in the head 2l.

To cause the piston assembly to revolve with the cylinder-Windlass 28,the rod 15 extends between and engages sockets in the cylinder heads 2!,26, respectively, and passes through the piston parallel with the shaft24. As the Windlass revolves to lower the stair, the rod 15 causes thepiston to revolve and advance along the thread 68 toward the head 21,displacing the oil 16 which slowly leaks between the threads 68 andwhere the rod passes through the piston. The oil being noncompressible,the slow leakage decelerates the rotation of the Windlass and thedescent of the stair. The rate of liquid displacement depends upon thefit of the threads, or a calibrated opening can be provided through thepiston to speed up the descent. About one inch of piston travel to eachfoot of descent is good general practice, to accomplish a speed of abouttwo feet per second of descent. Different ratios are available bychanging the pitch of the thread 68'or varying the displacement throughthe piston. The same variations in descent speed-can be alsoaccomplished by varying the viscosity of the oil 16. While oil ispreferred, a dry disk brake applied by an. appropriately pitched thread68 could be substituted for the oil displacing piston, for efiecting aprogressively applied frictional deceleration. While they are bothequivalent friction means, the oil system is preferable sincethe oilwill continue to flow until the stair comes to rest.

The liquid displaced in descent is impounded between the piston and thestuffing box 21. All Working parts within the cylinder-Windlass arelubricated by the oil 16.

In freezing climates it is advisable to leave an air space within thecylinder by not filling it completely with oil at the plug Tl. Shouldthe guide rods l2, [3 become ice encrusted the air space within thecylinder 28 will permit the stair to drop a foot or so before thedeceleration takes effect, this will cause the stair heads 58,

59 to jar the rods l2, l3 and shear off the ice during the remainder ofthe descent. Under such conditions it is advisable to enclose thehoisting mechanism including the head of the stair in an enclosing hood18, as in Fig. 5.

The guide rods l2, I3 join the two platforms 1,

2 to distribute the load between them.

This invention operates substantially as follows: The pin is removedfrom the hole 36 permitting the spring 35 to slide the pinion 30 intomesh withv the gear 29, see Fig. 3. The stair is then hoisted by turningthe crank 33 to wind the cable up on the Windlass 28. The operator holdsthe pawl 37 up in readiness to engage the gear 28 at the top of thelift. With the pawl securely holding the Windlass, the shaft 32 is slidto inoperative position and held by a pin through the hole 36. Duringthe ascent of the ladder the travel of the piston is reversed on thethread 68, restoring the oil impounded behind the piston to the chamberin front of the piston. Since a cup til with appropriate modifications,is equally applicable to many, other uses such as ships" ladders, lifeboat and various other hoists.

Having thus described this invention, what is claimed and desired to besecured by Letters Patent is: V p

1. In combination with the upper and lower platforms of a fire escape; apair of rigid guides terminating in a lower bracket having a fulcrumforward of said guides; a vertically movable stair engaging said guidesand slidable on said fulcrum.

2. In combination with the upper and lower platforms of a fire escape; apairof rigid guide rods extending between said platforms; a fulcrum onsaid lower'platform forward of said guides; a stair having its headengaging said 'rods and its rear edge slidable on said fulcrum.

.3. In combination with theupper and lower platforms of a fire escape;rigid guiding means extending between said platforms; a fulcrum on

